The order in which a mounter mounts electronic components on a printed circuit board or other substrate is conventionally optimized to minimize the tact time, which is to say, the time taken by mounting. As part of such optimization, it is necessary to optimize beforehand the order in which the various component feeders containing the components to be mounted are arranged within the mounter.
One example of such technology is the method for optimizing an order of component mounting disclosed by Japanese Laid-Open Patent Application H05-104364. This method is made up of a number of steps. In a first step, a number of component feeders are sorted into groups based on the mounting speeds of the components, and feeders containing components that are mounted at few positions on a substrate are paired off with feeders in the same group that contain components that are mounted at many positions, thereby evening out the total number of components mounted by each pair of feeders. In the second step, the order of the feeders is determined by arranging the feeder groups in order of mounting speed and arranging the feeders in each group in the pairs determined in the first step. Finally, in the third step, an optimization process is performed with only the mounting order of components as a parameter.
The above method avoids the need to perform a complex optimization of two parameters, namely the order of feeders and the mounting order of components, and can be completed in a short time since optimization is performed for a single parameter.
However, the above conventional optimization method has a premise that the head unit picks up only one component at a time from a component feeder during mounting. The method cannot be used by a mounter equipped with an advanced head unit (sometimes called a “line gang pickup head”) that picks up a number of components (such as ten components) and then mounts them on a substrate.
The recent explosion in demand for electronic appliances such as mobile phones and notebook computers has been accompanied by the development of mounters equipped with high-productivity line gang pickup heads that pick up many components and mount them on substrates. This has resulted in demands for a new optimization method for the order of component mounting for use by such advanced mounters.